After a recent lull, Trump returns to Twitter to lash out wildly at his many foes.

With cold, rainy weather in New Jersey forcing Donald Trump to take a break from his golf-a-thon summer vacation, Trump lashed out Monday morning on Twitter. He alternately attacked the press, boasted about his supposed popularity, and mocked allegations of “hoax Russia collusion.” He also leveled weird, personal attacks against a Democratic senator.

The nasty barrage marked the end to what had been a nearly week-long period of relatively mild tweets, where he had mostly focused on thanking his supporters and marketing his agenda.

With his new outburst, Trump obliterated the emerging talking point that Trump’s new chief of staff, John Kelly, has instituted a new, disciplined sense of professionalism in the Oval Office. “New Chief of Staff Kelly Moves Quickly to Tame Trump’s Tweets,” read the Bloomberg Politics headline last week.

Trump’s latest insecure tweets prove yet again that the thin-skinned politician is easily provoked and can’t be controlled.

Apparently watching CNN Monday morning, Trump saw Sen. Richard Blumenthal (D-CT) stress how the ongoing Russia investigation “must be pursued.” Blumenthal also discussed the importance of protecting special prosecutor Bob Mueller through legislation.

That sparked a Twitter denunciation of the “hoax Russian collusion” story and a swipe at Blumenthal’s military record during the Vietnam War.

What Blumenthal’s war record from nearly 50 years ago has to do with Trump’s deepening Russia scandal is unclear. But in 2010, the senator admitted to having previously misspoken about his war service. Trump, by contrast, never served in Vietnam. Instead, he received multiple medical deferments for a bone spur, despite the fact that he played three sports in high school. Trump remains an avid golfer today.

Trump started out his Twitter barrage by attacking The New York Times, which reported on Sunday that Republicans, including Vice President Mike Pence, are positioning themselves for a 2020 White House run, on the assumption that the scandal-plagued Trump won’t be in any position to seek re-election.

Trump then moved on to boasting about how strong his base of supporters is, even though his base is clearly shrinking as his approval rating dips even further. A Quinnipiac polls last week indicated Trump has reached new approval rating low of 33 percent.

The erosion’s being driven by the fact his base supporters — white voters without college degrees — are slowly abandoning him.

Trump’s new approval low arrived after Republicans failed after seven years to repeal and replace Obamacare, after Trump declared war on his attorney general, after his fired his doomed communications director, and after he announced a widely unpopular ban on transgender military members.

No wonder he’s so angry.